1. Field of the Invention
The invention relates generally to surgical methods and apparatus for the repair of the femur and more particularly related to methods and apparatus for repairing periprosthetic fractures and/or re-attaching the greater trochanter to the femur.
2. Description of the Prior Art
The bone structure of the hip joint often requires orthopedic surgery. Total hip replacements are performed most commonly because of progressively severe arthritis in the hip joint. The most common type of arthritis leading to total hip replacement is degenerative arthritis (osteoarthritis) of the hip joint. Other conditions leading to total hip replacement include bony fractures of the hip joint, and death (necrosis) of the femur. The progressively intense chronic pain together with impairment of daily function including walking, climbing stairs and even rising from a sitting position, eventually become reasons to consider a total hip replacement.
A total hip replacement is a surgical procedure whereby the diseased cartilage and bone of the hip joint is surgically replaced with artificial materials. As shown in FIG. 1, the normal hip joint is a ball and socket joint. The socket is a “cup-shaped” bone of the pelvis 180 called the acetabulum. The ball is at the head of the femur 170. Total hip joint replacement generally involves: (1) surgically removing the diseased ball and socket; and (2) replacing them with a metal ball and stem 210 inserted into the femur bone and an artificial plastic cup socket 220 (see FIG. 2). The metallic artificial ball and stem are referred to as the “prosthesis.” Upon inserting the prosthesis into the central core of the femur, it is fixed with a bony cement. Alternatively, a “cement-less” prosthesis may be used that allows bony in growth from the normal femur into the prosthesis stem. Even after hip replacement surgery, it often becomes necessary to perform further surgery due to further deterioration of the bone or to perform further repair of the replaced hip. If a patient falls and injures a replaced hip, the bone fracture will often occur at the distal tip of the prothesis, thereby requiring replacement of the prosthesis and/or repair of the femur.
Presently, a number of orthopedic surgical techniques exist for replacing or repairing the hip joint. A number of these total hip procedures require osteotomizing or removing the greater trochanter (illustrated by line 205 in FIG. 2). Removal of this portion of the femur provides the surgeon with access to the stem of the prosthesis to conduct the necessary hip replacement procedure. After the necessary hip replacement procedure, the greater trochanter must then be re-attached to the femur.
A few tools exist to enable re-attachment of the greater trochanter to the femur. One known technique utilizes a cable implant to hold bone portions together. Cables and/or wires secure the bones and the bone fragments in place. Typically, surgical cables are implanted using tensioning devices, which apply tension to a cable looped around the bone. Crimps are then added and deformed to clamp the cable loop in place. One example of such techniques is disclosed in U.S. Pat. No. 5,415,658, the entire writing of which is incorporated herein by reference. Another such example is the CABLE-READY brand cable grip system sold by Zimmer of Warsaw, Ind.
These techniques, however, rely entirely on cables to ensure that the device is securely fastened to the bone or bone fragments. Accordingly, it is desirable to provide a technique to re-attach the greater trochanter to the femur that provides an additional level of stability to the fracture site.
It is also desirable to provide a technique to repair periprosthetic fractures. Peri-prosthetic fractures have become increasingly common as more patients undergo total hip replacement, and may occur intraoperatively or at some time after surgery. The patient must then have an additional surgical procedure to repair the fracture.
It is further desirable to provide a device that can be fitted to femoral heads and femoral shafts of a variety of sizes and shapes without need for manufacture and inventory of an unreasonable number of differently sized models of the apparatus.